720
FXUS65 KBYZ 201849
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
1249 PM MDT MON JUL 20 2026
KEY MESSAGES
- WILDFIRE SMOKE WILL PRODUCE MINOR IMPACTS OVER OUR REGION
THROUGH TONIGHT.
- CHANCE OF THUNDERSTORMS RETURNS TO MAINLY MOUNTAINS TUESDAY,
THEN MOST OF AREA WEDNESDAY & THURSDAY. STORMS COULD PRODUCE
VERY HEAVY RAINFALL AND GUSTY WINDS.
- THIS WEEKEND IS LOOKING HOTTER & DRIER; A RETURN OF TRIPLE DIGIT
HEAT EXPECTED. FIRE DANGER MAY INCREASE.
DISCUSSION
THROUGH NEXT MONDAY...
SATELLITE IMAGERY SHOWS MOSTLY CLEAR SKIES WITHIN A ZONAL FLOW
ALOFT, BUT WE ARE STARTING TO SEE AN INCREASE IN MID/HIGH CLOUDS
FROM THE WEST. UPSTREAM RADAR IS SUGGESTIVE OF A BAND OF LIGHT
SHOWERS MOVING INTO SOUTH CENTRAL MT. FORECAST SOUNDINGS SHOW THIS
TO BE TIED TO VERY ELEVATED MOISTURE/INSTABILITY (BASED NEAR
500MB). WILL HOLD OFF ON ANY MENTION OF SHOWERS LATE THIS
AFTERNOON/TONIGHT AND WILL CONTINUE TO MONITOR. SURFACE ANALYSIS
SHOWS A 1020MB HIGH OVER AB, WHICH WILL SAG OVER EASTERN MT
TONIGHT IN RESPONSE TO A SHORTWAVE CURRENTLY OVER SOUTHERN SK.
THIS WILL BRING A SHIFT FROM N TO NE-E WINDS TONIGHT, SETTING UP A
"COOLER" DAY WITH EASTERLY WINDS TOMORROW. REGARDING AIR QUALITY,
MANY REPORTING STATIONS ARE SHOWING MODERATE AIR QUALITY. THE
BACKDOORING WINDS SHOULD IMPROVE NEAR SURFACE SMOKE TONIGHT, BUT
THE WINDS ALOFT WILL CONTINUE TO SUPPORT HAZY SKIES RESULTING FROM
SMOKE TRANSPORT FROM THE NUMEROUS WILDFIRES IN WA/OR.
PER THE MONSOONAL FLOW, AIR MASS MOISTENS CONSIDERABLY TOMORROW
W/ PWATS RISING BACK TO ANOMALOUSLY HIGH VALUES (1.2-1.4").
FORCING SEEMS LACKING TOMORROW SO THE GREATEST POTENTIAL FOR WET
THUNDERSTORMS WILL BE OVER SOUTHERN MOUNTAINS/FOOTHILLS, EKING
INTO SOUTHEAST MT TOMORROW NIGHT W/ A SOUTHEASTERLY LLJ. MODELS
ARE CONSISTENTLY SHOWING A DISTINCT SHORTWAVE EMERGING FROM THE
GREAT BASIN WEDNESDAY, WHICH SHOULD YIELD A GREATER CHANCE OF
THUNDERSTORMS OVER MOST OF THE REGION (THOUGH STILL HIGHEST POPS
IN WEST AND SOUTH PORTIONS OF THE CWA). WET THUNDERSTORM POTENTIAL
CONTINUES THURSDAY ON THE BACK SIDE OF THIS WAVE. ALL TOLD, ANY
THUNDERSTORMS THE NEXT 3 DAYS WILL HAVE THE POTENTIAL TO PRODUCE
VERY HEAVY RAINFALL AND LOCALIZED WET MICROBURSTS. GIVEN THE
EXPECTATION OF GREATEST COVERAGE OF STORMS OVER OUR SOUTH, BURN
SCARS SUCH AS ROBERTSON DRAW, EAST SIDE AND ELK WILL NEED TO BE
WATCHED FOR A RISK OF FLASH FLOODING. TEMPERATURES WILL BE
SEASONABLE THROUGH THE PERIOD.
EXPECT HOTTER & DRIER CONDITIONS FRIDAY THRU MONDAY, WITH BUILDING
CONFIDENCE BASED ON ENSEMBLES/CLUSTER ANALYSES. MONSOON MOISTURE
WILL BE REDUCED AND HEIGHTS WILL BUILD WELL INTO THE 590S. THERE
REMAINS A SLIGHT CHANCE (10-20%) OF THUNDERSTORMS ON THESE DAYS,
BUT THEY WILL BE HIGH-BASED AND DRIER. WITH 700MB TEMPERATURES
RISING TO +16C TO +18C WE WILL LIKELY SEE TRIPLE DIGITS, PERHAPS
OVER MULTIPLE DAYS ESPECIALLY FOR NOTORIOUSLY HOTTER SPOTS IN THE
EAST (E.G. MILES CITY AND BROADUS). MIXED WINDS WILL BE BREEZY
DURING THE DAYTIMES, AND THERE MAY ALSO BE A PRE-FRONTAL DAY OF
CONCERN IF THE RIDGE FLATTENS INTO EARLY NEXT WEEK. ALL OF THESE
DETAILS ARE HIGHLY UNCERTAIN NOW, BUT OVERALL EXPECT FIRE DANGER
TO INCREASE OVER THIS PERIOD OF TIME.
AS A SIDE NOTE, THE BILLINGS AIRPORT HAS NOT (SINCE 1934) REACHED
100F ON JULY 25TH...THE ONLY SUCH DAY IN JULY, AND IN FACT THE
ONLY DAY BETWEEN JUNE 23 AND AUGUST 19. THIS MIGHT BE THE YEAR THE
CLIMATE ODDITY FINALLY ENDS. CURRENT FORECAST FOR SATURDAY IS
101F. THE FLY IN THE OINTMENT, HOWEVER, COULD BE WILDFIRE SMOKE AS
WINDS ALOFT DO SUPPORT SMOKE TRANSPORT FROM FIRES IN WA/OR/CA.
STAY TUNED.
JKL
AVIATION
18Z DISCUSSION...
WILDFIRE SMOKE WILL CREATE SLANT RANGE VISIBILITY REDUCTIONS
ACROSS THE FORECAST AREA. WHILE MVFR VIS IS UNLIKELY AT ANY SITE,
IT CANNOT BE RULED OUT THROUGH 00Z. A STRAY SHOWER IS POSSIBLE
THIS AFTERNOON/EVENING ACROSS THE ENTIRE FORECAST REGION (10%
CHANCE). WINDS WILL SLOWLY SHIFT TO NE THROUGH THE DAY TODAY WITH
A WEAK FROPA PUSHING THROUGH KBIL/KSHR AROUND 02Z WHICH COULD
BRING NE WIND GUSTS UP TO 30 KTS. VFR CONDITIONS ARE FORECAST TO
PREVAIL. WMR
PRELIMINARY POINT TEMP/POPS
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 065/089 066/092 068/091 067/100 069/101 069/096 067/097
10/B 11/U 44/T 11/U 21/G 20/U 11/U
LVM 057/088 057/090 057/090 057/096 060/098 058/095 057/096
01/B 15/T 85/T 11/U 22/T 22/W 21/U
HDN 062/090 063/094 066/091 063/102 066/103 067/098 065/098
20/B 11/U 55/T 11/G 21/G 20/U 11/U
MLS 063/086 064/093 067/092 066/103 070/104 071/100 067/099
00/B 00/U 12/T 10/G 21/G 20/U 10/U
4BQ 063/088 065/091 066/087 064/100 069/102 070/098 067/097
00/B 40/B 55/T 10/U 11/G 11/U 11/B
BHK 057/083 058/089 061/090 061/101 067/104 067/099 063/098
11/B 00/U 12/T 10/G 11/G 21/U 11/U
SHR 058/091 061/090 061/086 059/096 064/098 064/094 062/095
00/B 34/T 78/T 21/U 01/U 11/U 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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